When selecting a field in layout mode, you can display the following tabs in the inspector :
What you are asking for a Full Access tabs for a field. You can still have users that you allow to change layouts but should not be near anything in the tabs you are suggesting.
This would definitely need security! As does the ability to create fields (as we have in field picker). I suppose if you do not allow creation of fields (within field picker or via Table View, Browse Mode), then you would also NOT be able to see/use this Inspector 'extension for fields'. However, I do like the idea of something in the Inspector (or by the field picker) that gives access to these setting rather than having to go back to Manage Database.
Waiting for more feedback before voting,
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